High speed sheet feeding and overlapping system



M. C. LYMAN April 25, 1967 HIGH SPEED SHEET FEEDING AND OVERLAPPING SYSTEM Filed June 22, 1964 INVENTOR MERTON C. LYMAN W M??? mOPUmFmO II IIIIII A TTORNEYS United States Patent 3,315,956 HIGH SPEED SHEET FEEDING AND UVERLAPBPING SYSTEM Merton C. Lyman, Willimautic, Conn., assignor to Smith and Winchester Manufacturing Company, South Windham, Conn, a corporation of Connecticut Filed June 22, 1964, Ser. No. 376,734 7 tllaims. (Cl. 271-46) This invention relates generally to an improved high speed sheet feeding and sheet overlapping system for use in a high speed sheeter and dual layboy system. This sheet feeding and overlapping system is an improvement of the system which is the subject of the United States Patent No. 3,218,897, issued Nov. 23, 1965, in the name of Dudley H. Geigenmiller et al. for a Sheet Feeding Apparatus, and assigned to the same assignee as this application.

The principal object of this invention is to provide for emcient high speed feeding and overlapping of sheets of paper after they have been cut from a web by a sheeter and prior to the stacking of the sheets in a layboy.

Another object of this invention is to provide a means for disabling the sheet feeding mechanism when an abnormal gap occurs between sheets being fed to the overlap mechanism, thereby maintaining the desired overlap of sheets being fed to the layboy.

A further object of this invention is to provide means for positively retaining in the overlapping mechanism the last sheet preceding an abnormal gap in successive sheets and simultaneously disabling sheet feeding means which would otherwise withdraw the sheet from the overlapping mechanism and feed it to the layboy stacking device.

Still another object of this invention is to provide such a sheet feeding and overlapping system wherein the resumption of the normal spacing between sheets being fed to the overlapping mechanism returns the sheet feeding means to operative condition so that successive overlapped sheets are fed thereby to the stacking device.

Other objects will be in part obvious and in part pointed out more in detail hereinafter.

The invention accordingly consists in the features of construction, combination of elements and arrangement of parts which will be exemplified in the construction hereafter set forth and the scope of the application which will be indicated in the appended claims.

In the drawings:

FIGURE 1 shows the preferred form of a high speed sheet feeding and sheet overlapping system embodying this invention, and

FIGURE 2 is an enlarged view of the sheet feeding brake roll and disabling mechanism therefor.

It should be understood at the outset that this sheet feeding and overlapping system may be applied to a plurality of parallel paths of sheets formed by a sheeter as shown in detail in the above'cited pending application. However, for the purpose of understanding this invention, this system will be described as applied to the feeding and overlapping of only a single path of sheets.

In FIGURE 1 there is shown a preferred embodiment of this high speed sheet feeding and overlapping system. In order more fully to appreciate the advantages of this system, it is necessary to understand some of the problems which occur in high speed sheeters. After the sheets are cut from the paper web, they are then fed to a stacking device known as a layboy. However, because of the high speed of travel of these sheets, it is necessary to overlap the sheets prior to their entry into the layboy. That is, the leading edge of each sheet is caused to overlap the trailing edge of the preceding sheet before the sheets are fed to the layboy. In this invention, such a result is obtained generally by feeding the sheets from a high speed conveying system to a lower speed conveying system whereby the sheets are effectively retarded or braked as they reach the lower speed system thereby permitting the leading edge of the following sheet to overlap the trailing edge of the first sheet. The overlapped sheets are then fed by the low speed conveying system to the layboy.

However, another problem occurs in such high speed sheeters when an abnormally large gap appears between sheets being fed to the overlapping mechanism so that the normal retardation of each sheet is insufficient to form an overlap with the following sheet. Such an abnormal gap may be formed when sheets are deflected from the main path for the purpose of sampling, sorting, rejecting, etc. Let us consider the case of rejecting sheets when a flaw is detected in the paper web prior to the sheet cutting operation. A suitable flaw detector is positioned between a paper web feed roll and the sheet cutting apparatus to sense a flaw that may occur in the web. These devices are not shown in the drawing since they form no part of this invention and are shown in the said. pending application. When a flaw is detected, a signal is sent from the flaw detector to operate sheet deflecting means which deflects flaw-containing sheets from the main sheet path leading to a first layboy to an alternate path which may also lead to a second layboy. This second layboy then stacks the rejected sheets in the same manner as the first layboy.

When sheets are rejected, a larger than normal gap appears between the sheets being fed to the sheet overlapping station of the main path. Consequently some means must be provided to retain at the overlapping station the last sheet preceding the flaw so that overlapping occurs when a flawless sheet again is fed along the main path. If such means were not provided, a plurality of spaced single sheets would be fed from the high speed feeding mechanism to the low speed feeding mechanism and to the layboy. Such a condition causes the leading edges of the following sheets to collide with the trailing edges of preceding sheets thereby causing jam-ups in the low speed section and layboy.

These problems are solved by this invention by the provision of an improved sheet feeding and overlapping means for use with a high speed sheeter and layboy wherein the proper overlap between successive sheets is maintained when an abnormally large gap occurs between sheets approaching the overlapping station.

Let us now return to FIGURE 1. There is shown a diagrammatic side view of a high speed sheet feeding and overlapping system for a sheeting .and layboy apparatus. High speed tapes 1% are supported by a pair of high speed pulleys 12 and 14, roll 14 being the driving roll. In the view shown in FIGURE 1, it is not apparent that there is more than one tape driven by the pulleys I2 and 14. However, in high speed sheeters it is common to use a plurality of relatively narrow tapes or belts to carry the sheets rather than a single wider belt.

Engaging a portion of the belt is another set of high speed belts 18 having an inclined portion. 19 and driven by suitable pulleys 20, 22 and 24. Sheets fed between tapes 18 and 10 are normally conveyed to another set of high speed tapes 26 which engage tapes It) in an area downstream from tapes 18. Positioned in this area is a suitable photoelectric device 27 consisting of alight source 28 and a photocell 29 for sensing an abnormally large gap between the passing sheets. Device 27 is located so that light falls between tapes 10 and 26 onto the photocell. As a sheet leaves the tapes 26, it drops upon a suction plate 30 in the overlapping station of the system. Since the sheet is traveling at a very high rate of speed at this point, the leading edge thereof continues on to a plurality of lower speed tapes 32 driven by suitable pulleys 33 and 35. The leading edge of the sheet also enters the nip 31 formed between a brake roll 34 and a cooperating roller 36. Brake roll 34 engages the upper surfaces of tapes 32 and roller 36 engages the lower surfaces of tapes 32. Roll 34 is positively driven at the same speed as the low speed tapes 32. It should be noted that roll 34 in the dimen sion not shown contains circumferential slots to allow high speed tapes to pass therethrough without engaging roll 34. As the trailing edge of a sheet leaves high speed tapes 26, the leadin edge thereof enters the nip formed between rolls 34 and 36. Each sheet is then fed along the tapes 32 to a suitable sheet stacking device such as a layboy. Such a device forms no part of this invention and is not illustrated.

A solenoid operated valve 40 responds to a signal from the flaw detector (not shown) to operate a pneumatic cylinder and piston actuator 42 which is connected via a bell crank 44 to a sheet deflector 46. The electrical output from the photoelectric sensing means 27 is fed to suitable controls which form no part of this invention. Amplified output signals from controls 50 energize a normally closed solenoid valve 52 to open the valve and connect a vacuum source (not shown) to an opening in the top of suction plate 39. A manually operated, normally open valve 54 also connects suction plate 30 to a vacuum source. Output signals from controls 50 also energize a solenoid valve 55 for selectively connecting a source of compressed air (not shown) to a roll separating mechanism which creates a gap between rolls 34 and 36 to eliminate the nip therebetween. This roll separating mechanism is shown in more detail in FIGURE 2.

As shown in FIGURE 2, brake roll 34 is fixed to a shaft 56 which rotates in a bearing 58 mounted in a carriage 60. Carriage 60 is movable along the length of tapes 32 and travels on a pair of supporting rods 62 which are fixed at the ends thereof to a pair of standards 64. A manually rotatable lead screw 66 is threaded through a lug in carriage 60 so that an operator may rotate the wheel 68 in order to vary the position of the rolls 34 and 36 relative to suction plate 30 in accordance with the length of the sheets being fed onto plate 30. Carriage 6t should be positioned so that the leading edge of each sheet enters the nip 31 just as the trailing edge of the sheet leaves tapes 26 and falls upon suction plate 30.

Fixed in the lower portion of carriage 60 is a shaft 70 to which is pivotally mounted a bell crank 72 which is rotated by a pneumatic actuator 74. Conduits 76 connect actuator 74 through valve 55 to a source of compressed air. Roller 36 is rotatably mounted at the end of the horizontal arm of hell crank 72.

In operation, paper sheets are fed between high speed tapes 1% and 18. If no signal is applied from the flaw detector to solenoid valve 40, the sheets continue onto high speed tapes 26. As a sheet leaves the high speed tapes 26 it enters the overlapping section including the suction plate 34 The leading edge of the sheet enters the nip 31 formed between brake roll 34 and roller 36 simultaneously With the departure of the sheets trailing edge from tapes 26. Carriage 6t) is manually adjusted to provide this relationship.

The suction applied to the opening in the top surface of plate 30 via the open valve 54 which is connected to a vacuum source pulls down the trailing edge of the sheet. This action of suction plate 3%} accomplishes two purposes. First, sheets traveling at such high speed tend to cling to the under surface of high speed tapes 10 rather than dropping by gravity onto low speed tapes 32. One function of suction plate 30 is to pull the trailing edge of each sheet down against plate 30 so that the leading edge of the following sheet does not jam up against the trailing edge of the first sheet. Second, the effect of the suction of plate 30 on the trailing edge of a sheet together with the braking effect produced by brake roll 34 and tapes 32 operating at a speed lower than tapes l0 and 26 retards or slows down the sheet so that the leading edge of the following sheet overlaps the trailing edge of the first sheet. Consequently, a successive stream of overlapped sheets is fed by tapes 3?. and rollers 34, 36 to the stacking device or layboy. Valve 54 is open during this operation to provide a relatively low suction at the surface of plate 3d. Valve 52 is normally closed during this operation since it is only opened when it is desired to provide a greater suction on plate 30 in order to retain a sheet in the overlapping station.

Let us now look at the situation which occurs when a flaw is detected in the Web from which the sheets are being cut. In this case, a signal from the flaw detector energizes solenoid valve 4t to connect pneumatic actuator 42 to a source of compressed air. Actuator 42, acting through hell crank 44, pivots deflector 46 clockwise. Deficctor 4.6 engages the top surface of the sheets passing thereunder and diverts or deflects them onto the inclined portion 19 of high speed tapes 18. The rejected sheets may then be fed through a sheet feeding and overlapping system identical to the one described above, that is, including a photosensitive gap sensing means, an overlapping station, a brake roll, and a stacking device or layboy.

When a sheet is deflected onto tape 18, an abnormally large gap appears between sheets being fed onto suction plate 30. Photosensitive means 27 senses this gap and sends an electrical signal to controls 54? which sends simultaneous amplified signals to solenoid valves 52 and 55. Normally closed valve 52 is thereby opened to increase the suction applied to suction plate 30. Normally closed valve 55 is also thereby opened to connect pneumatic actuator '74 to a source of compressed air. Actuator 74 rotates bellcrank 72 counterclockwise so that roller 36 is disengaged from tapes 32 and a gap is formed between brake roll 34 and roll 36. Consequently, the positive feeding action produced by the nip normally formed between rolls 34 and 36 is removed so that there is relatively little positive force tending to pull a sheet from plate 3i). The combination of the increased suction at the surface of plate 30 and the separation of rolls 34 and 36 causes a sheet to be retained in their overlapping station, i.e., with its trailing edge on plate 3% and its leading edge just below brake roll 34. This condition is maintained so long as sheets are being deflected onto the inclined portion 19 of tapes 18 and photosensing means 27 does not detect another sheet on tapes 26.

When the flaw in the web is no longer sensed, solenoid valve 40 is de-energized and deflector 46 is returned by any suitable means to the position shown in FIGURE 1. Consequently, the sheets being fed between tapes 10 and 18 are fed onto tapes 26 instead of onto the inclined portion 19 of tapes 18. When the leading edge of a sheet travels between the light source 28 and photocell 7.9 of the photo-sensing device 27, the light beam is broken and the photo-cell no longer sends a signal to controls 5%. Thereupon, solenoid valve 52 is de-energized to remove the additional suction from plate 39. Solenoid valve 55 is also tie-energized to permit roller 36 to return to its nipforming position with brake roll 34. These operations are synchronized so that the sheet being fed onto suction plate 3t overlaps the trailing edge of the sheet that was retained to form the normal overlap and successive overlapped sheets are once again fed by tapes 32 to a layboy as previously described.

A preferred embodiment of this invention has been described above, and it is understood that various modifications thereof will be obvious to those skilled in the art without departing from the spirit of the invention. Therefore, it is intended that the true scope of this invention be limited only as defined in the appended claims.

As will be apparent to persons skilled in the art, various modifications and adaptations of the structure above described will become readiiy apparent without departure from the spirit and scope of the invention, the scope of which is defined in the appended claims.

I claim:

1. In a sheet feeding and overlapping mechanism hav ing means for conveying a plurality of sheets along a path, means for overlapping successive sheets and means for detecting an abnormal gap between successive sheets, the improvement comprising sheet retaining means selectively operable on the upstream edge of a sheet for retaining said sheet, feeding means positioned downstream from said retaining means for acting on each of a stream of successive sheets to feed the same along said path, and means responsive to an abnormal gap between successive sheets for simultaneously disabling said feeding means and operating said retaining means, said feeding means being continuously operable when said retaining means is inoperative to effect a positive sheet feeding and braking action on each of a stream of successive sheets.

2. A sheet handling system wherein a plurality of sheets are fed along a path comprising selectively operable sheet retaining means disposed in the path of the sheets and operable on an upstream edge of a sheet for retaining the same, sheet feeding means positioned downstream from said retaining means, and means responsive to an abnormal gap between successive sheets for operating said retaining means and disabling said sheet feeding means, said feeding means being continuously operable when said retaining means is inoperative to effect a positive sheet feeding and braking action on each of a stream of successive sheets.

3. The system as defined in claim 2 wherein said sheet feeding means comprises a movable roller and a driven fixed roller which normally engages each of a stream of successive sheets and wherein said sheet responsive means comprises means for moving said movable roller away from said fixed roller for disengaging the same from a sheet only when said retaining means is operated.

4. The system as defined in claim 3 wherein said sheet responsive means further comprises suction producing means which is effective to retain a sheet at the position of said retaining means when said driven roller is out of engagement with a sheet.

5. A high speed sheet feeding and sheet overlapping system for conveying sheets along a path from a sheeter to a stacking device comprising a high speed conveying means for receiving the sheets from the sheeter, a low speed conveying means for feeding overlapped sheets to the stacking device, and an overlapping section located between said high and low speed conveying means, sheet deflecting means associated with said high speed means for diverting sheets from said path, means positioned between said overlapping means and said high speed means for detecting an abnormally large gap between successive sheets in said path, a driven fixed roller associated with said low speed means for engaging and feeding each of a stream of successive sheets from said overlapping means to said low speed means, the various means disposed along said path being located relative to each other so that the trailing edge of each sheet enters said overlapping means when the leading edge thereof is engaged by said fixed roller, a second roller movable toward and away from said fixed roller for selectively forming a nip therebetween for braking and feeding each of a stream of successive sheets, and means responsive to said detecting means for moving said second roller away from said fixed roller to disrupt the nip therebetween only upon the occurrence of an abnormally large gap between successive sheets in said path for disengaging a leading edge of a sheet from said fixed roller and retaining the trailing edge of said sheet in said overlapping means.

6. The system as defined in claim 5 wherein said overlapping means comprises a suction producing device which is responsive to said detecting means to retain the trailing edge of said sheet when said fixed roller is disengaged.

7. The system as defined in claim 6 further comprising means for supplying to said overlapping means a suction of a value insufficient to retain a sheet but sufficient to retard a sheet so that, when there is no abnormally large gap between sheets, the leading edge of the next following sheet overlaps the trailing edge of the retarded sheet before the sheets are fed to the stacking device.

References Cited by the Examiner UNITED STATES PATENTS 2,240,423 4/1941 Spiess 271-56 2,381,430 8/1945 Belluche 271-69 X 2,551,468 5/1951 Schutt 271-57 2,852,256 9/1958 Faulls et al. 271-76 3,178,174 4/1965 Schneider 271-46 3,218,897 11/1965 Geigenmiller et a1. 271-46 X 3,173,684 3/1965 Binzoni et a1. 271-57 3,232,605 2/1966 Plum-mer et a1. 271-46 M. HENSON WOOD, ]R., Primary Examiner. ROBERT B. REEVES, Examiner. C. H. SPADERNA, J. N. ERLICH, Assistant Examiners. 

1. IN A SHEET FEEDING AND OVERLAPPING MECHANISM HAVING MEANS FOR CONVEYING A PLURALITY OF SHEETS ALONG A PATH, MEANS FOR OVERLAPPING SUCCESSIVE SHEETS AND MEANS FOR DETECTING AN ABNORMAL GAP BETWEEN SUCCESSIVE SHEETS, THE IMPROVEMENT COMPRISING SHEET RETAINING MEANS SELECTIVELY OPERABLE ON THE UPSTREAM EDGE OF A SHEET FOR RETAINING SAID SHEET, FEEDING MEANS POSITIONED DOWNSTREAM FROM SAID RETAINING MEANS FOR ACTING ON EACH OF A STREAM OF SUCCESSIVE SHEETS TO FEED THE SAME ALONG SAID PATH, AND MEANS RESPONSIVE TO AN ABNORMAL GAP BETWEEN SUCCESSIVE SHEETS FOR SIMULTANEOUSLY DISABLING SAID FEEDING MEANS AND OPERATING SAID RETAINING MEANS, SAID FEEDING MEANS BEING CONTINUOUSLY OPERABLE WHEN SAID RETAINING MEANS IS INOPERATIVE TO EFFECT A POSITIVE SHEET FEEDING AND BRAKING ACTION ON EACH OF A STREAM OF SUCCESSIVE SHEETS. 